Here is the table from MDv 416T (firing regulations for U-boats), for this method. If you run the numbers it is 1.94. Why that is the case, Pisces and I lay out in previous posts. At the bottom is a rule of thumb to use 2 as that makes mental math easier.
1.852 will of course work at reasonable ranges because the difference is a matter of fractions of a knot. But simply multiplying by it is a misunderstanding of how to apply the 1852 m/nm conversion, and not based on what is actually happening. If taught, a concept should be taught correctly. Now that people know why it is 1.94, why not just use that? Or 2 like the historical rule of thumb?
